scholarly journals A Numerical Approach of the Influence of Water Temperature in the Extinction of Fire Developed in Closed Spaces

2022 ◽  
Vol 960 (1) ◽  
pp. 012006
Author(s):  
P Cozma ◽  
D Pavel ◽  
C A Safta ◽  
A Chisacof
Keyword(s):  
Numerical Simulation ◽  
Fire Behavior ◽  
Numerical Approach ◽  
Water Mist ◽  
Simulation Approach ◽  
Influence Of Water ◽  
Different Temperatures ◽  
Fire Extinguish ◽  
Different Diameters ◽  
In Fire

Abstract The aim of this work is to make a visual investigation of the fire behavior during the extinguish process with water mist at different temperatures, different diameters of the nozzle and different angles of diffusion jet, too. It was used a numerical simulation approach to analyze 24 scenarios regarding the influence of mist water in fire extinguish process. The main test was focused on a given enclosure with dimensions of 1.0 × 1.0 × 3.0 m and the fire source placed inside, in the middle. The enclosure is considered opened on the upper part. From the numerical simulation values, we concluded the best scenario in fire extinguish process using water mist.

scholarly journals Development and evaluation of a numerical simulation approach to predict metal artifacts from passive implants in MRI

2021 ◽  
Author(s):  
Tobias Spronk ◽  
Oliver Kraff ◽  
Jakob Kreutner ◽  
Gregor Schaefers ◽  
Harald H. Quick
Keyword(s):  
Numerical Simulation ◽  
Field Strength ◽  
Testing Procedure ◽  
Numerical Approach ◽  
Medical Implants ◽  
Simulation Approach ◽  
Metal Artifacts ◽  
Mr Image ◽  
Metallic Implants ◽  
Field Strengths

Abstract Objective This study presents the development and evaluation of a numerical approach to simulate artifacts of metallic implants in an MR environment that can be applied to improve the testing procedure for MR image artifacts in medical implants according to ASTM F2119. Methods The numerical approach is validated by comparing simulations and measurements of two metallic test objects made of titanium and stainless steel at three different field strengths (1.5T, 3T and 7T). The difference in artifact size and shape between the simulated and measured artifacts were evaluated. A trend analysis of the artifact sizes in relation to the field strength was performed. Results The numerical simulation approach shows high similarity (between 75% and 84%) of simulated and measured artifact sizes of metallic implants. Simulated and measured artifact sizes in relation to the field strength resulted in a calculation guideline to determine and predict the artifact size at one field strength (e.g., 3T or 7T) based on a measurement that was obtained at another field strength only (e.g. 1.5T). Conclusion This work presents a novel tool to improve the MR image artifact testing procedure of passive medical implants. With the help of this tool detailed artifact investigations can be performed, which would otherwise only be possible with substantial measurement effort on different MRI systems and field strengths.

Flashover and instabilities in fire behavior

1980 ◽  
Vol 38 ◽  
pp. 159-171 ◽  
Author(s):  
P.H. Thomas ◽  
M.L. Bullen ◽  
J.G. Quintiere ◽  
B.J. McCaffrey
Keyword(s):  
Fire Behavior ◽  
In Fire

Numerical Simulation Study on High-Temperature Ventilated Cavitating Flow Considering the Compressibility of Gases

2012 ◽  
Vol 569 ◽  
pp. 395-399
Author(s):  
Jing Zhao ◽  
Guo Yu Wang ◽  
Yan Zhao ◽  
Yue Ju Liu
Keyword(s):  
Numerical Simulation ◽  
State Equation ◽  
Field Structure ◽  
Cavitating Flow ◽  
Simulation Approach ◽  
Gas Velocity ◽  
Simulation Data ◽  
Ventilated Cavity ◽  
Supercavitating Flow ◽  
Fluctuation Range

A numerical simulation approach of ventilated cavity considering the compressibility of gases is established in this paper, introducing the gas state equation into the calculation of ventilated supercavitating flow. Based on the comparison of computing results and experimental data, we analyzes the differences between ventilated cavitating flow fields with and without considered the compressibility of gases. The effect of ventilation on the ventilated supercavitating flow field structure is discussed considering the compressibility of gases. The results show that the simulation data of cavity form and resistance, which takes the compressibility of gases into account, accord well with the experimental ones. With the raising of ventilation temperature, the gas fraction in the front cavity and the gas velocity in the cavity increase, and the cavity becomes flat. The resistance becomes lower at high ventilation temperature, but its fluctuation range becomes larger than that at low temperature.

Changes in fire behavior caused by fire exclusion and fuel build-up vary with topography in California montane forests, USA

2022 ◽  
Vol 304 ◽  
pp. 114255
Author(s):  
Catherine Airey-Lauvaux ◽  
Andrew D. Pierce ◽  
Carl N. Skinner ◽  
Alan H. Taylor
Keyword(s):  
Fire Behavior ◽  
Montane Forests ◽  
Fire Exclusion ◽  
In Fire

Numerical Analysis of Fire Behavior of a Large Space Pre-Stressed Steel Structure under Fire

2011 ◽  
Vol 71-78 ◽  
pp. 3729-3732
Author(s):  
Ming Zhou ◽  
Zhi Guo Xie ◽  
Xin Tang Wang
Keyword(s):  
Numerical Analysis ◽  
Fire Behavior ◽  
Thermal Response ◽  
Structural Response ◽  
Steel Structure ◽  
Large Space ◽  
Fire Source ◽  
Lattice Shell ◽  
In Fire ◽  
Influence Degree

The computational model of numerical analysis of a suspended pre-stressed steel reticulated shell subjected to fire load is established with using the software Marc. Based on the model presented here, numerical analysis of thermal response and structural response of the pre-stressed steel structure are computed. The different space height and different rise-span ratio are considered for analysis of response temperature, displacements and stresses of the pre-stressed lattice shell under fire for one fire source. It is also shown that displacement of the node right above the inner cable is the maximum among the four nodes presented here as the fire source is located at the position right below the second-ring cable of the structure. It is concluded that the influence degree of space height of the structure on the fire response of the structure is not great, but rise-span ratio has obvious and great effect on displacements and stresses of the pre-stressed steel structure with large span in fire.

scholarly journals On Numerical Simulation Approach for Multiple Resonance Modes in Servo Systems

2017 ◽  
Vol 2017 ◽  
pp. 1-7
Author(s):  
Qixin Zhu ◽  
Hongli Liu ◽  
Yiyi Yin ◽  
Lei Xiong ◽  
Yonghong Zhu
Keyword(s):  
Numerical Simulation ◽  
Mathematical Model ◽  
Closed Loop ◽  
Resonance Mode ◽  
Servo Control ◽  
Simulation Approach ◽  
Servo Systems ◽  
Resonance Modes ◽  
Resonant Part ◽  
The Mathematical Model

Mechanical resonance is one of the most pervasive problems in servo control. Closed-loop simulations are requisite when the servo control system with high accuracy is designed. The mathematical model of resonance mode must be considered when the closed-loop simulations of servo systems are done. There will be a big difference between the simulation results and the real actualities of servo systems when the resonance mode is not considered in simulations. Firstly, the mathematical model of resonance mode is introduced in this paper. This model can be perceived as a product of a differentiation element and an oscillating element. Secondly, the second-order differentiation element is proposed to simulate the resonant part and the oscillating element is proposed to simulate the antiresonant part. Thirdly, the simulation approach for two resonance modes in servo systems is proposed. Similarly, this approach can be extended to the simulation of three or even more resonances in servo systems. Finally, two numerical simulation examples are given.

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